Add support for LIBXML_NOEMPTYTAG for save()

[hopfi2k]

Would be fantastic to see support for the LIBXML_NOEMPTYTAG flag for the save() and xml() export methods. Really missing this one ;-)

[daniele-orlando]

I was wondering whether to include or not this feature in a future release but I don't know any real usecase in which this feature could be really helpful.

Can you report here your usecase which could take benefit from implementing the LIBXML_NOEMPTYTAG flag?

Thank you.